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If a^2b^2c^3 = 4500. Is b+c = 7 ?

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If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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New post Updated on: 26 Aug 2018, 21:29
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If \(a^2b^2c^3\) = 4500. Is b+c = 7 ?

(1) a, b and c are positive integers
(2) a > b

Originally posted by GMATBaumgartner on 17 Oct 2012, 01:52.
Last edited by Bunuel on 26 Aug 2018, 21:29, edited 3 times in total.
Edited the question.
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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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New post 17 Oct 2012, 03:56
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GMATBaumgartner wrote:
If a^2b^2c^3 = 4500. Is b+c = 7 ?

(1) a, b and c are positive integers
(2) a > b


what would be the most efficient way to approach this within 2 mins?


Given: \(a^2*b^2*c^3 = 4500=2^2*3^2*5^3\). Question: is \(b+c=7\)

(1) a, b and c are positive integers --> sure it's possible that \(a=3\), \(b=2\) and \(c=5\) and in this case the answer will be YES but it's also possible that \(a=2\), \(b=3\) and \(c=5\) and in this case the answer will be NO. Not sufficient.

(2) a > b. Clearly insufficient.

(1)+(2) Note that we are not told that a, b and c are prime numbers, so again it's possible that \(a=3>2=b\) and \(c=5\) and in this case the answer will be YES but for example it's also possible that \(a=2^2*3^2=6^2\), \(b=1\) and \(c=5\) (\(a^2*b^2*c^3 =6^2*1^2*5^3=4500\)) and in this case the answer will be NO. Not sufficient.

Answer: E.

Hope it's clear.
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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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New post 17 Oct 2012, 04:13
Thank you bunuel. I completely overlooked the part they there is NO mention of then as primes!

Is there any post where you sum up the important such 'overlook-ables' that we must crosscheck before marking a statement Sufficient or Not sufficient.

Thanks in advance.I am in the final leg of my prep,any advise would be much appreciated.
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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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New post 17 Oct 2012, 05:03
Very often I overlook the possibilty of 0 in equalties. i.e. I check for only +ve and -ve numbers.

A list of the aforementioned "overlookables" would help a lot.
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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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New post 17 Oct 2012, 19:49
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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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New post 23 Oct 2012, 06:40
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GMATBaumgartner wrote:
Thank you bunuel. I completely overlooked the part they there is NO mention of then as primes!

Is there any post where you sum up the important such 'overlook-ables' that we must crosscheck before marking a statement Sufficient or Not sufficient.

Thanks in advance.I am in the final leg of my prep,any advise would be much appreciated.


Below are some links on DS strategies, tips and tricks that might help you:
data-sufficiency-strategy-guide-130264.html
trouble-with-quant-some-tips-traps-that-might-help-you-34329.html
tips-on-approaching-ds-questions-104945.html
http://gmatclub.com/blog/2010/01/verita ... questions/
http://gmatclub.com/blog/2010/09/elimin ... fficiency/
http://gmatclub.com/blog/2011/08/gmat-d ... tion-type/
http://gmatclub.com/blog/2011/08/must-k ... trategies/
http://gmatclub.com/blog/2011/08/kaplan ... questions/

Hope it helps.
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PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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New post 19 Jul 2013, 01:22
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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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New post Updated on: 19 Jul 2013, 12:49
Hi,

Sorry I think that answer is B. Here is my opinion: we are just able to re-write 4500=(3^2)*(2^2)*(5^3), right?

just we don't know that which one of 3 or 2 is a & b, correct?

statement 2 is giving us a>b then we know that a=3 and b=2 and problem solved.

I don't know where I went wrong? Can you explain my fault?


Edit: I found it!

Originally posted by zazoz on 19 Jul 2013, 12:41.
Last edited by zazoz on 19 Jul 2013, 12:49, edited 1 time in total.
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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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New post 19 Jul 2013, 12:47
zazoz wrote:
Hi,

Sorry I think that answer is B. Here is my opinion: we are just able to re-write 4500=(3^2)*(2^2)*(5^3), right?

just we don't know that which one of 3 or 2 is a & b, correct?

statement 2 is giving us a>b then we know that a=3 and b=2 and problem solved.

I don't know where I went wrong? Can you explain my fault?


Please read the solution: if-a-2b-2c-3-4500-is-b-c-140842.html#p1132262

Pay attention to the examples given:

(1)+(2) Note that we are not told that a, b and c are prime numbers, so again it's possible that \(a=3>2=b\) and \(c=5\) and in this case the answer will be YES but for example it's also possible that \(a=2^2*3^2=6^2\), \(b=1\) and \(c=5\) (\(a^2*b^2*c^3 =6^2*1^2*5^3=4500\)) and in this case the answer will be NO. Not sufficient.

Answer: E.

Hope it's clear.
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Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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New post 19 Jul 2013, 12:49
Bunuel wrote:
zazoz wrote:
Hi,

Sorry I think that answer is B. Here is my opinion: we are just able to re-write 4500=(3^2)*(2^2)*(5^3), right?

just we don't know that which one of 3 or 2 is a & b, correct?

statement 2 is giving us a>b then we know that a=3 and b=2 and problem solved.

I don't know where I went wrong? Can you explain my fault?


Please read the solution: if-a-2b-2c-3-4500-is-b-c-140842.html#p1132262

Pay attention to the examples given:

(1)+(2) Note that we are not told that a, b and c are prime numbers, so again it's possible that \(a=3>2=b\) and \(c=5\) and in this case the answer will be YES but for example it's also possible that \(a=2^2*3^2=6^2\), \(b=1\) and \(c=5\) (\(a^2*b^2*c^3 =6^2*1^2*5^3=4500\)) and in this case the answer will be NO. Not sufficient.

Answer: E.

Hope it's clear.


yeah, I got it, thanks
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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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New post 16 Mar 2016, 21:56
If a^2b^2c^3 = 4500. Is b+c = 7 ?
(a^2) (b^2) (c^3) =4500=(30^2) 5
(abc)^2 c= (30^2) 5
If a, b and c are positive integers then we may have c=5 and abc=30 => ab=6

(1) a, b and c are positive integers
a, b and c are positive integers then we may have c=5 and abc=30 => ab=6.
but a=3,b=2 => b+c=7
a=6, b=1 => b+c=6 INSUFFICIENT
(2) a > b
a and b may be fractions and many combinations are posssible for a and b. INSUFFICIENT

combining 1 and 2
a=3,b=2 => b+c=7
a=6, b=1 => b+c=6 INSUFFICIENT

Hence E
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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ?  [#permalink]

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Re: If a^2b^2c^3 = 4500. Is b+c = 7 ? &nbs [#permalink] 25 Jul 2018, 11:00
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